We know that dolphins and bats echolocate, but less is known about the ultrasonic vocalizations of other animals– including the northern short-tailed shrew. Some suggest they don’t even make ultrasonic vocalizations at all, but instead produce noise when they move. In this episode, Valerie Eddington and Laura Kloepper (both currently at University of New Hampshire and previously at St. Mary’s College) discuss their research into the sound made by these creatures.
(Like the episode? Don’t miss the article in JASA!)
Warmer Climate Could Cause Puerto Rico’s Frogs to Croak #ASA184
Rising temperatures leave their mark in the distinctive calls of the coqui frog.
Media Contact: Ashley Piccone AIP Media 301-209-3090 media@aip.org
CHICAGO, May 8, 2023 – The coqui frog is one of Puerto Rico’s most iconic animals. It gets its name from its distinctive two-note call, “co-qui,” which can be heard throughout the island every night. The males of the species produce these calls to mark their territory and ward away rivals, but scientists can also use them to study the changing climate.
Peter Narins of the University of California, Los Angeles will describe changes in the calls of the coqui frog over a 23-year period in his talk, “Climate change drives frog call change in Puerto Rico: Predictions and implications.” The presentation will take place Monday, May 8, at 2:40 p.m. Eastern U.S. in room Chicago F/G, as part of the 184th Meeting of the Acoustical Society of America running May 8-12 at the Chicago Marriott Downtown Magnificent Mile Hotel.
Male coqui calling in El Yunque, Puerto Rico. Credit: K. Wells
Over two decades ago, Narins recorded the sounds of the coqui frog along the slopes of Puerto Rico’s El Yunque Peak. His team discovered the calls changed based on elevation. Like all amphibians, coqui frogs are highly sensitive to changes in temperature. On cold mountain peaks, the frogs grow larger than in warmer valleys, and this size discrepancy is reflected in their calls.
“Coqui that produced short, high-pitched calls at high rates lived near the base of the mountain, while the calls of animals living near the mountain’s peak were longer, lower-pitched, and repeated less frequently,” said Narins.
Upon returning to the mountain two decades later, Narins and a team including colleague Sebastiaan Meenderink discovered that every frog call had grown higher in pitch.
“In order to record a call with certain characteristics we had to move to a slightly higher altitude,” said Meenderink. “It was as if all the animals had moved up the mountain.”
This mini-migration corresponds with the temperature shift induced by climate change and foreshadows a dire future for the coqui. As temperatures continue to rise, the frogs will continue to retreat up the mountain until they run out of room.
“For now, the consequences are not dire,” said Meenderink. “A barely perceptible change in frog body size and call has little impact on the environment. However, if left unabated, the temperature increase will eventually cause a collapse of the coqui population, which will be catastrophic for the Puerto Rican ecosystem.”
ASA PRESS ROOM In the coming weeks, ASA’s Press Room will be updated with newsworthy stories and the press conference schedule at https://acoustics.org/asa-press-room/.
LAY LANGUAGE PAPERS ASA will also share dozens of lay language papers about topics covered at the conference. Lay language papers are 300 to 500 word summaries of presentations written by scientists for a general audience. They will be accompanied by photos, audio, and video. Learn more at https://acoustics.org/lay-language-papers/.
PRESS REGISTRATION ASA will grant free registration to credentialed and professional freelance journalists. If you are a reporter and would like to attend the meeting or virtual press conferences, contact AIP Media Services at media@aip.org. For urgent requests, AIP staff can also help with setting up interviews and obtaining images, sound clips, or background information.
ABOUT THE ACOUSTICAL SOCIETY OF AMERICA The Acoustical Society of America (ASA) is the premier international scientific society in acoustics devoted to the science and technology of sound. Its 7,000 members worldwide represent a broad spectrum of the study of acoustics. ASA publications include The Journal of the Acoustical Society of America (the world’s leading journal on acoustics), JASA Express Letters, Proceedings of Meetings on Acoustics, Acoustics Today magazine, books, and standards on acoustics. The society also holds two major scientific meetings each year. See https://acousticalsociety.org/.
University of Minnesota 75 East River Parkway Minneapolis, MN 55455 United States
Christopher Feist Christopher Milliren Lori Arent Julia B. Ponder Peggy Nelson Edward J. Walsh
Popular version of 3aABb4 – Behavioral responses of bald eagles (Haliaeetus leucocephalus) to acoustic stimuli in a laboratory setting Presented at the 184 ASA Meeting Read the abstract at https://doi.org/10.1121/10.0018607 Please keep in mind that the research described in this Lay Language Paper may not have yet been peer reviewed.
The ultimate goal of this project is to protect eagles by discouraging these charismatic birds from entering the airspace of wind energy facilities. The specific question under consideration centers on whether or not an acoustic cue, a sound, can be used for that purpose, to steer eagles away from harm’s way. Our specific goal in this particular study was to take the next step along our overall research path and determine if behaviors of bald eagles in particular were affected by different sound stimuli in a controlled laboratory environment.
Perhaps to be expected, behavioral responses varied significantly. Some birds explored their immediate airspace avidly, while others exhibited a more restrained set of behavioral responses to sound stimulation.
To get a feeling for the task, consider the reaction of this eagle to a sound stimulus in a quiet laboratory setting .
To collect these data, a bird was placed in a sound-damped room and the experiment was conducted from a control center just outside the exposure space. Birds were videotaped as sounds were delivered to one of two speakers and a group of unbiased judges was asked to determine (1) whether the bird responded to the sound based on its behavior, (2) to qualitatively assess the strength of the response, and (3) to identify the behaviors associated with the response. Twelve sounds were tested and judges were instructed to observe the eagle during a specified time window without knowing which sound, if any, had been played. Spectrograms of the sounds tested are shown in the figure.
By far the most common response was an attempt to localize the sound source based on head turning toward a speaker, although birds also frequently tilted their heads in response to stimuli. Females were slightly more responsive to sound stimuli than males, and not surprisingly, stimuli that elicited a higher number of responses also elicited stronger or more evident responses. Complex and natural sounds, for example, sounds produced by eagles, eaglets and pesky mobbing crow sounds, elicited more and stronger responses than man-made stimuli. Generally, bald eagles were fairly accurate in locating the direction that the sound originated, and, as before, females performed better than males.
The results from this study provide a critical step in an effort to protect eagles as we move away from the use of fossil fuels and rely more on wind power. We come away from this study with a better understanding of the types of sound signals that elicit more and stronger responses in bald eagles, and with the confidence that we will be able to objectively assess behavioral responses in more natural settings. We now know what these magnificent birds can hear, and we know that certain sound stimuli are more effective than others in evoking behavioral responses, taking us one step closer to our ultimate goal, to save bald eagles from undesirable outcomes and to give wind facility developers the tools needed to manage their facilities in an even more eco-friendly manner.
University of Victoria Victoria, BC V5T 4H3 Canada
Additional authors: William Halliday, Stan E. Dosso, Xavier Mouy, Andrea Niemi, Stephen Insley
Popular version of 1aAB8 – I know what you did last winter: Bowhead whale anomalous winter acoustic occurrence patterns in the Beaufort Sea, 2018-2020 Presented at the 184 ASA Meeting Read the abstract at https://doi.org/10.1121/10.0018030
The Arctic is warming at an alarming pace due to climate change. As waters are warming and sea ice is shrinking, the arctic ecosystems are responding with adaptations that we only recently started to observe and strive to understand. Here we present the first evidence of bowhead whales, endemic baleen whales to the Arctic, breaking their annual migration and being detected year-round at their summer grounds.
Whales, positioned at the top of the food web, serve as excellent bio-indicators of environmental change and the health of marine ecosystems. There are more than 16,000 bowhead whales in the Bering-Chukchi-Beaufort (BCB) population in the Western Arctic. The BCB bowheads spend their winters in the ice-free Bering Sea, and typically start a journey early each spring of over 6000 km to summer feeding grounds in the Beaufort Sea, returning to the Bering Sea in early fall when ice forms on the Beaufort Sea (Figure 1). But how stable is this journey in our changing climate?
Figure 1. Map showing migration route of BCB bowhead whales and the wider study area.
The Amundsen Gulf (Figure 1), in the Canadian Arctic Archipelago of the Beaufort Sea, is an important summer-feeding area for the BCB whales. However, winter inaccessibility and harsh conditions year-round make long-term observation of marine wildlife here challenging. Passive acoustic monitoring has proven particularly useful for monitoring vocal marine animals such as whales in remote areas, and offers a remarkable opportunity to explore where and when whales are present in the cold darkness of Arctic waters. Figure 2 shows examples of two types of bowhead whale vocalizations (songs and moans) together with other biological and environmental sounds recorded in the Amundsen Gulf.
Figure 2. Examples of spectrograms recorded in the Amundsen Gulf of bowhead whale songs on the left, and bowhead whale moans on the right. Spectrograms are visual representations of sound, indicating the pitch (frequency) and loudness of sounds as a function of time. Spectrograms on the left include bearded seal calls (trills) interfering with the bowhead songs. Spectrograms on the right include other ambient sounds (ice noise) that interfere with the bowhead moans. Image adapted from authors’ original paper.
Examples of characteristic calls of bowhead whales recorded during 2018-2019 in the southern Amundsen Gulf.
In September of 2018 and 2019 we deployed underwater acoustic recorders at five sites in the southern Amundsen Gulf and recorded the ocean sound for two years to detect bowhead whale calls and quantify the whale’s seasonal and geographic distribution. In particular, we looked for any disruptions to their typical migration patterns. And sure enough, there it was.
A combination of automated and manual analysis of the acoustic recordings revealed that bowhead whales were present at all sites, as shown for 3 sites (CB50, CB300 and PP) in Figure 3. Bowhead calls dominated the acoustic data from early spring to early fall, during their summer migration, confirming the importance of the area as a core foraging site for this whale population. But surprisingly, the analysis uncovered a fascinating anomaly in bowhead whale behavior: bowhead calls were detected at each site through the winter of 2018-2019, representing the first clear evidence of bowhead whales overwintering at their summer foraging grounds (Figure 3). This is a significant departure from their usual migratory pattern. However, analysis of the 2019-2020 recordings did not indicate whales over-wintering that year. Hence, it is not yet clear if the over-wintering was a one-time event or the start of a more stable shift in bowhead whale ecology due to climate change. The variability in bowhead acoustic presence between the two years may be partly explained by differences in sea ice coverage and prey density (zooplankton), as summarized in Figure 4.
Figure 3. Number of days with acoustic detections per month for bowhead whales for sites CB50 (blue), CB300 (green), and PP (red) in 2018-2019. The yellow shaded areas represent time periods at each station when the ice concentration was below 20% (“ice-free”), grey areas when ice concentration was 20%-70% (“shoulder season”), and white areas when ice concentration was greater than 70%. Image adapted from authors’ original paper.
Figure 4. Graphical summary of the objectives and major results of the study.
The findings of this study have important implications for understanding how climate change is affecting the Arctic ecosystem, and highlights the need for continued monitoring of Arctic wildlife. Passive acoustic monitoring can provide data on how whale ecology is responding to a changing environment, which can be used to inform conservation efforts to better protect Arctic ecosystems and their inhabitants.
The pups possess an innate control of their voice and an understanding of rhythm.
Media Contact: Ashley Piccone AIP Media 301-209-3090 media@aip.org
NASHVILLE, Tenn., Dec. 9, 2022 – Humans appear to be one of the only animals capable of speech, which requires a range of skills and mental abilities. Among them, vocal learning — the ability to learn to produce new sounds —is critical for developing language. Only a handful of animals possess this trait, including humans, bats, whales, seals, and elephants.
Andrea Ravignani studies the vocal learning of seal pups. Credit: Connie Edwards/Kleve Zoo
However, simply possessing the ability to create new sounds is not enough to unlock language. Studying whether animals possess additional language-related skills can help us understand what it takes to learn speech and reveal the history of its evolution.
Andrea Ravignani of the Max Planck Institute for Psycholinguistics will discuss his work linking vocal learning with vocal plasticity and rhythmic capacity in his session, “Vocal learning, chorusing seal pups, and the evolution of rhythm.” The presentation will take place on Dec. 9 at 9:50 a.m. Eastern U.S. in Grand Hall A, as part of the 183rd Meeting of the Acoustical Society of America running Dec. 5-9 at the Grand Hyatt Nashville Hotel.
Ravignani and colleagues studied seal pups’ vocal plasticity, or how well they can adjust their own voices to compensate for their environment. They found that seal pups can change the pitch and volume of their voices, much like humans. The ability to change volume is common, but changing pitch, or fundamental frequency, is rare in animals.
“Seals may have this capacity due to convergent evolution: vocal plasticity may be a trait which evolved independently in multiple lineages due to similar evolutionary pressures,” said Ravignani. “For the case of humans and seals, plasticity and vocal learning may be associated with either advanced breathing control or singing abilities in both species.”
The team also tested the ability of seal pups to identify rhythmic sounds using recordings of other seals. They altered some of those recordings by changing tempos and adding rhythms to see how the young seals would react. Seal pups paid significantly more attention to recordings with regular rhythms and fast tempos.
“We can conclude that very young and untrained seals can discriminate between other seals’ vocalization based on their rhythmic properties,” said Ravignani. “Another mammal, apart from us, shows rhythm processing and vocalization learning; perhaps these two skills coevolved in both humans and seals.”
ASA PRESS ROOM In the coming weeks, ASA’s Press Room will be updated with newsworthy stories and the press conference schedule at https://acoustics.org/asa-press-room/.
LAY LANGUAGE PAPERS ASA will also share dozens of lay language papers about topics covered at the conference. Lay language papers are 300 to 500 word summaries of presentations written by scientists for a general audience. They will be accompanied by photos, audio, and video. Learn more at https://acoustics.org/lay-language-papers/.
PRESS REGISTRATION ASA will grant free registration to credentialed and professional freelance journalists. If you are a reporter and would like to attend the meeting or virtual press conferences, contact AIP Media Services at media@aip.org. For urgent requests, AIP staff can also help with setting up interviews and obtaining images, sound clips, or background information.
ABOUT THE ACOUSTICAL SOCIETY OF AMERICA The Acoustical Society of America (ASA) is the premier international scientific society in acoustics devoted to the science and technology of sound. Its 7,000 members worldwide represent a broad spectrum of the study of acoustics. ASA publications include The Journal of the Acoustical Society of America (the world’s leading journal on acoustics), JASA Express Letters, Proceedings of Meetings on Acoustics, Acoustics Today magazine, books, and standards on acoustics. The society also holds two major scientific meetings each year. See https://acousticalsociety.org/.
